Research On The Geometrical Error Identification Of Numerical Control Machine Tools Based On Three Dimensional Stop-gauge

The measuring of numerical control machine tools'volumetric error is the key point of error compensation, this paper research on a new measuring equipment used for machine tools'precision inspecting named three dimensional stop-gauge. A error model for three axis NC machine tools is founded, and the characters of the three dimensional stop-gauge when it is used to measuring the machine tools'volumetric error are deeply discussed. The mainly aspects of this paper are as follows:First, the actuality of error measuring and error modeling in and outside our country is discussed, the aim and the method of machine tools'error measuring has been nailed down. The advantages and disadvantages of every error measuring equipment are analyzed, in order to explain the essentiality of empolder the three dimensional stop-gauge equipment.Secondly, the detailed structure of the three dimensional stop-gauge is explained, the principle of the three dimensional stop-gauge is introduced and the formula of measuring the micro-displacement of the spatial discrete point and measuring the departure of the spatial step are detailedly analyzed. Meanwhile, the measuring accuracy of the equipment and confirmed the influence of the measuring accuracy especially caused by the equipment's manufacturing error and the equipment installing error are analyzed.Thirdly, the calibration method and measuring method of the three dimensional stop-gauge has been researched. The experiment on coefficient calibration of cone is carried out, the influence of the measuring accuracy of the equipment caused by the manufacturing accuracy of the cone is validated. When using the equipment the measuring error may be inducted in because of the twice installments during the measuring process, the measuring error can be sharply reduced by limiting the pose of the equipment. An notice of using the measuring probe sensor devices which may cause damage to some of operation is given described in details.Finally, the experiments on validating the accuracy of the three dimensional stop-gauge have been carried out. The volumetric error between the calibrating machine tools and the measuring machine tools has been calculated out after the step distance calibrating and step distance measuring. Then, use the cross grid encoder to measuring out two machine tools errors, according to the result compared with the three dimensional stop-gauge's error measuring data we may know the accuracy of the error measuring equipment. It is proofed that the three dimensional stop-gauge have high precision in machine tools'volumetric error measuring. Combined with the error identification model of the NC machine tools, the volumetric error identify model of the NC machine tools based on the three dimensional stop-gauge was introduced. It is very helpful to the NC machine tools'accuracy checks when the new products leave factory and the error compensation of the old NC machine tools'accuracy renew.The three dimensional stop-gauge has characteristics of convenient,high precision of error measuring and low cost, it is very suitable to be applied and it is very important to enhance the accuracy of machine tools'machining.